Typically, a cartridge, of whatever caliber, comprises a brass case or shell which has a charge of powder, a primer, and a bullet or projectile. After firing, essentially nothing remains of the original cartridge except the brass case, which is the most expensive element. The brass case is commonly thrown away, or sold for scrap, or recycled through a tedious and labor intensive reloading process.
U.S. Pat. No. 3,228,333 discloses an electrically actuated cartridge comprising a plastic cartridge case, which is significantly less expensive than the brass case of a conventional cartridge. However, the disclosed electrically actuated cartridge appears to be relatively fragile in construction and expensive to manufacture in that it relies upon a wire filament extending through the propellant charge or the inclusion of a finely divided electrically conductive material within the propellant and includes the bullet in the electrical circuit. Although the disclosed arrangement may be advantageous in dispensing with a primer assembly and in the provision of a plastic case, it may be impractical in terms of constituting an inexpensive, sturdy and reliable equivalent of a conventional brass case cartridge.
It is also known in the prior art to electrically ignite an explosive powder or the like by means of a spark gap structure rather than by means of a relatively fragile fine wire resistance element. Representative of such devices is the spark gap detonator of U.S. Pat. No. 3,754,506. However, these devices appear to be relatively complex in structure, frequently requiring an intricate assembly of sub-elements.